The patch titled console: prevent registered consoles from dumping old kernel message over again has been removed from the -mm tree. Its filename was console-prevent-registered-consoles-from-dumping-old-kernel-message-over-again.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: console: prevent registered consoles from dumping old kernel message over again From: Feng Tang <feng.tang@xxxxxxxxx> For a platform with many consoles like: "console=tty1 console=ttyMFD2 console=ttyS0 earlyprintk=mrst" Each time when the non "selected_console" (tty1 and ttyMFD2 here) get registered, the existing kernel message will be printed out on registered consoles again, the "mrst" early console will get some same message for 3 times, and "tty1" will get some for twice. As suggested by Andrew Morton, every time a new console is registered, it will be set as the "exclusive" console which will dump the already existing kernel messages. Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx> Cc: Greg KH <gregkh@xxxxxxx> Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/printk.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff -puN kernel/printk.c~console-prevent-registered-consoles-from-dumping-old-kernel-message-over-again kernel/printk.c --- a/kernel/printk.c~console-prevent-registered-consoles-from-dumping-old-kernel-message-over-again +++ a/kernel/printk.c @@ -113,6 +113,11 @@ static unsigned con_start; /* Index into static unsigned log_end; /* Index into log_buf: most-recently-written-char + 1 */ /* + * If exclusive_console is non-NULL then only this console is to be printed to. + */ +static struct console *exclusive_console; + +/* * Array of consoles built from command line options (console=) */ struct console_cmdline @@ -476,6 +481,8 @@ static void __call_console_drivers(unsig struct console *con; for_each_console(con) { + if (exclusive_console && con != exclusive_console) + continue; if ((con->flags & CON_ENABLED) && con->write && (cpu_online(smp_processor_id()) || (con->flags & CON_ANYTIME))) @@ -1230,6 +1237,11 @@ void console_unlock(void) local_irq_restore(flags); } console_locked = 0; + + /* Release the exclusive_console once it is used */ + if (unlikely(exclusive_console)) + exclusive_console = NULL; + up(&console_sem); spin_unlock_irqrestore(&logbuf_lock, flags); if (wake_klogd) @@ -1464,6 +1476,12 @@ void register_console(struct console *ne spin_lock_irqsave(&logbuf_lock, flags); con_start = log_start; spin_unlock_irqrestore(&logbuf_lock, flags); + /* + * We're about to replay the log buffer. Only do this to the + * just-registered console to avoid excessive message spam to + * the already-registered consoles. + */ + exclusive_console = newcon; } console_unlock(); console_sysfs_notify(); _ Patches currently in -mm which might be from feng.tang@xxxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html